不同补锌剂量对大鼠海马nNOS蛋白表达影响

Effects of zinc supplementation at different levels on nNOS protein expression in hippocampus of rats

目的探讨补锌对临床亚健康干预的合理剂量以及高锌对脑功能的影响及机制。方法采用Y-型迷宫行为学测试结合免疫组化卵白素-生物素-过氧化酶复合物法(ABC)法,分别观察大鼠海马结构不同亚区内神经元型一氧化氮合酶(nNOS)蛋白表达的变化。结果适量补锌〔200 mg/(kg.bw)饲料锌水平〕可使大鼠海马结构CA1、CA3、齿状回的nNOS表达增加(P<0.05),促进动物的学习记忆功能。而超高剂量补锌〔≥600 mg/(kg.bw)饲料锌水平〕,可使大鼠海马结构CA1、CA3、齿状回的nNOS表达减少(P<0.05),损害动物的学习记忆能力。结论适量补锌对大鼠学习记忆功能有促进作用,其机制可能与海马nNOS蛋白表达水平上调有关。

Objective To find out the effective limits of zinc supplementation for subhealth and to study the possible mechanism. Methods Y - labyrinth test was used to exam the function of learning and memory, and ABC immunohistochemistry were applied to measure the levels of protein expression of nNOS in hippocampus of rats, respectively. Results Zinc supplementation at lower levels [such as 200 mg/（ kg· bw） zinc in feeds] could improve learning and memory function by increasing the protein expression of nNOS in hippocampal formation and subregions of CA1 and CA3 and dentate gyrus of rats; excessive zinc supplementation beyond the limits [600 mg/（ kg· bw） zinc in feeds] could impair learning and memory by decreasing the protein expression of nNOS in hippocampus of animals. Conclusion Zinc supplementation at lower levels could improve learning and memory function of rats, and increase of the protein expression of nNOS in hippocampus might be one of the most important mechanisms of zinc affecting learning and memory.